Question: How to take professional quality macros of jewelry

I have been doing a bit of macro jewelry photography for a customer of mine (this is my first time tackling this type of photography). I'm using a D80 with mirror lock activated, quantaray 28mm-90mm lens with macro setting locked at 90mm, ISO100, light tent, three 5500K continuous lights and tripod of course with a wired shutter release attachment. My results are very good in my opinion for what I'm being paid, but I'm not achieving the absolutely flawless results I've seen with high exposure professional jewelry photography. If anyone here does this type of work, could you fill me in on some equipment used and other techniques. Thanks.

I was a jeweler for a decade and my GIA appraiser did all her own shots, with a Cannon Rebel XTI. I guess what I am asking how are your pictures developing out? I've seen plenty of almost flawless shot, but what I have experienced is shooting jewelry is not an easy task.

I actyually just did a jewelry shoot for a family member. Its not as difficult as you think. My set up was Nikon D90, SB-600, jewelyr, piece of white paper. If you bounce the light off a ceiling or diagnoally up behind you at a wall/ceiling, the photos turn out quite nicely. I will post some later.

Thanks for replies. Here are some samples photos I've taken and processed with PSE7. There will be more than 50 images when the project is finished. Obviously here the files sizes are smaller than the originals, so you may see some pixelation, but this gives you a pretty good idea. I feel they came out good for my very first time doing this sort of thing. But what I eventually want to achieve is flawless representations of the originals, like what you might see in an advertisement at a retailer. If any of you are seasoned in this, what sort of lenses and bodies do you use? Any other info is welcome. Thanks in advance for your input.